[PATCH 0/3] power: reset: Convert Power-Off driver to tristate

[PATCH 0/3] power: reset: Convert Power-Off driver to tristate

[Lee Jones]

Provide support to compile the Power-Off driver as a module.

Elliot Berman (2):
  reboot: Export reboot_mode
  power: reset: Enable tristate on restart power-off driver

Lee Jones (1):
  arch: Export machine_restart() instances so they can be called from
    modules

 arch/arc/kernel/reset.c            | 1 +
 arch/arm/kernel/reboot.c           | 1 +
 arch/arm64/kernel/process.c        | 1 +
 arch/csky/kernel/power.c           | 1 +
 arch/h8300/kernel/process.c        | 1 +
 arch/hexagon/kernel/reset.c        | 1 +
 arch/m68k/kernel/process.c         | 1 +
 arch/microblaze/kernel/reset.c     | 1 +
 arch/mips/kernel/reset.c           | 1 +
 arch/mips/lantiq/falcon/reset.c    | 1 +
 arch/mips/sgi-ip27/ip27-reset.c    | 1 +
 arch/nios2/kernel/process.c        | 1 +
 arch/openrisc/kernel/process.c     | 1 +
 arch/parisc/kernel/process.c       | 1 +
 arch/powerpc/kernel/setup-common.c | 1 +
 arch/riscv/kernel/reset.c          | 1 +
 arch/s390/kernel/setup.c           | 1 +
 arch/sh/kernel/reboot.c            | 1 +
 arch/sparc/kernel/process_32.c     | 1 +
 arch/sparc/kernel/reboot.c         | 1 +
 arch/um/kernel/reboot.c            | 1 +
 arch/x86/kernel/reboot.c           | 1 +
 arch/xtensa/kernel/setup.c         | 1 +
 drivers/power/reset/Kconfig        | 2 +-
 kernel/reboot.c                    | 2 ++
 25 files changed, 26 insertions(+), 1 deletion(-)


-- 
2.32.0.554.ge1b32706d8-goog

[PATCH 1/3] arch: Export machine_restart() instances so they can be called from modules

[Lee Jones]

A recent attempt to convert the Power Reset Restart driver to tristate
failed because of the following compile error (reported once merged by
Stephen Rothwell via Linux Next):

  ERROR: "machine_restart" [drivers/power/reset/restart-poweroff.ko] undefined!

This error occurs since some of the machine_restart() instances are
not currently exported for use in modules.  This patch aims to rectify
that.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---

NB: If it's safe to omit some of these, let me know and I'll revise the patch.

 arch/arc/kernel/reset.c            | 1 +
 arch/arm/kernel/reboot.c           | 1 +
 arch/arm64/kernel/process.c        | 1 +
 arch/csky/kernel/power.c           | 1 +
 arch/h8300/kernel/process.c        | 1 +
 arch/hexagon/kernel/reset.c        | 1 +
 arch/m68k/kernel/process.c         | 1 +
 arch/microblaze/kernel/reset.c     | 1 +
 arch/mips/kernel/reset.c           | 1 +
 arch/mips/lantiq/falcon/reset.c    | 1 +
 arch/mips/sgi-ip27/ip27-reset.c    | 1 +
 arch/nios2/kernel/process.c        | 1 +
 arch/openrisc/kernel/process.c     | 1 +
 arch/parisc/kernel/process.c       | 1 +
 arch/powerpc/kernel/setup-common.c | 1 +
 arch/riscv/kernel/reset.c          | 1 +
 arch/s390/kernel/setup.c           | 1 +
 arch/sh/kernel/reboot.c            | 1 +
 arch/sparc/kernel/process_32.c     | 1 +
 arch/sparc/kernel/reboot.c         | 1 +
 arch/um/kernel/reboot.c            | 1 +
 arch/x86/kernel/reboot.c           | 1 +
 arch/xtensa/kernel/setup.c         | 1 +
 23 files changed, 23 insertions(+)

diff --git a/arch/arc/kernel/reset.c b/arch/arc/kernel/reset.c
index fd6c3eb930bad..ae4f8a43b0af4 100644
--- a/arch/arc/kernel/reset.c
+++ b/arch/arc/kernel/reset.c
@@ -20,6 +20,7 @@ void machine_restart(char *__unused)
 	pr_info("Put your restart handler here\n");
 	machine_halt();
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_power_off(void)
 {
diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index 0ce388f154226..2878260efd130 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -150,3 +150,4 @@ void machine_restart(char *cmd)
 	printk("Reboot failed -- System halted\n");
 	while (1);
 }
+EXPORT_SYMBOL(machine_restart);
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index b4bb67f17a2ca..cf89ce91d7145 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -212,6 +212,7 @@ void machine_restart(char *cmd)
 	printk("Reboot failed -- System halted\n");
 	while (1);
 }
+EXPORT_SYMBOL(machine_restart);
 
 #define bstr(suffix, str) [PSR_BTYPE_ ## suffix >> PSR_BTYPE_SHIFT] = str
 static const char *const btypes[] = {
diff --git a/arch/csky/kernel/power.c b/arch/csky/kernel/power.c
index 923ee4e381b81..b466c825cbb3c 100644
--- a/arch/csky/kernel/power.c
+++ b/arch/csky/kernel/power.c
@@ -28,3 +28,4 @@ void machine_restart(char *cmd)
 	do_kernel_restart(cmd);
 	asm volatile ("bkpt");
 }
+EXPORT_SYMBOL(machine_restart);
diff --git a/arch/h8300/kernel/process.c b/arch/h8300/kernel/process.c
index 46b1342ce515b..8203ac5cd33ec 100644
--- a/arch/h8300/kernel/process.c
+++ b/arch/h8300/kernel/process.c
@@ -66,6 +66,7 @@ void machine_restart(char *__unused)
 	local_irq_disable();
 	__asm__("jmp @@0");
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_halt(void)
 {
diff --git a/arch/hexagon/kernel/reset.c b/arch/hexagon/kernel/reset.c
index da36114d928f0..433378d52063c 100644
--- a/arch/hexagon/kernel/reset.c
+++ b/arch/hexagon/kernel/reset.c
@@ -19,6 +19,7 @@ void machine_halt(void)
 void machine_restart(char *cmd)
 {
 }
+EXPORT_SYMBOL(machine_restart);
 
 void (*pm_power_off)(void) = NULL;
 EXPORT_SYMBOL(pm_power_off);
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index da83cc83e7912..e0264704686e9 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -57,6 +57,7 @@ void machine_restart(char * __unused)
 		mach_reset();
 	for (;;);
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_halt(void)
 {
diff --git a/arch/microblaze/kernel/reset.c b/arch/microblaze/kernel/reset.c
index 5f4722908164d..902fbe3777846 100644
--- a/arch/microblaze/kernel/reset.c
+++ b/arch/microblaze/kernel/reset.c
@@ -41,3 +41,4 @@ void machine_restart(char *cmd)
 	pr_emerg("Reboot failed -- System halted\n");
 	while (1);
 }
+EXPORT_SYMBOL(machine_restart);
diff --git a/arch/mips/kernel/reset.c b/arch/mips/kernel/reset.c
index 6288780b779e7..2d3193a3cf68b 100644
--- a/arch/mips/kernel/reset.c
+++ b/arch/mips/kernel/reset.c
@@ -99,6 +99,7 @@ void machine_restart(char *command)
 	pr_emerg("Reboot failed -- System halted\n");
 	machine_hang();
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_halt(void)
 {
diff --git a/arch/mips/lantiq/falcon/reset.c b/arch/mips/lantiq/falcon/reset.c
index 261996c230cf6..80dd9759ffa55 100644
--- a/arch/mips/lantiq/falcon/reset.c
+++ b/arch/mips/lantiq/falcon/reset.c
@@ -51,6 +51,7 @@ static void machine_restart(char *command)
 		(void *)WDT_REG_BASE);
 	unreachable();
 }
+EXPORT_SYMBOL(machine_restart);
 
 static void machine_halt(void)
 {
diff --git a/arch/mips/sgi-ip27/ip27-reset.c b/arch/mips/sgi-ip27/ip27-reset.c
index 5ac5ad6387343..a3f8f4498b7c5 100644
--- a/arch/mips/sgi-ip27/ip27-reset.c
+++ b/arch/mips/sgi-ip27/ip27-reset.c
@@ -29,6 +29,7 @@
 #include "ip27-common.h"
 
 void machine_restart(char *command) __noreturn;
+EXPORT_SYMBOL(machine_restart);
 void machine_halt(void) __noreturn;
 void machine_power_off(void) __noreturn;
 
diff --git a/arch/nios2/kernel/process.c b/arch/nios2/kernel/process.c
index c5f916ca6845f..6f9459e8ae4ed 100644
--- a/arch/nios2/kernel/process.c
+++ b/arch/nios2/kernel/process.c
@@ -51,6 +51,7 @@ void machine_restart(char *__unused)
 	: "r" (cpuinfo.reset_addr)
 	: "r4");
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_halt(void)
 {
diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c
index eb62429681fc8..12c3022c46387 100644
--- a/arch/openrisc/kernel/process.c
+++ b/arch/openrisc/kernel/process.c
@@ -61,6 +61,7 @@ void machine_restart(char *cmd)
 	pr_emerg("Reboot failed -- System halted\n");
 	while (1);
 }
+EXPORT_SYMBOL(machine_restart);
 
 /*
  * Similar to machine_power_off, but don't shut off power.  Add code
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index b144fbe29bc16..05e9f03124b64 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -96,6 +96,7 @@ void machine_restart(char *cmd)
 	while (1) ;
 
 }
+EXPORT_SYMBOL(machine_restart);
 
 void (*chassis_power_off)(void);
 
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 74a98fff2c2f9..54ebae540dd7d 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -159,6 +159,7 @@ void machine_restart(char *cmd)
 
 	machine_hang();
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_power_off(void)
 {
diff --git a/arch/riscv/kernel/reset.c b/arch/riscv/kernel/reset.c
index ee5878d968cc1..596a36b91eaa2 100644
--- a/arch/riscv/kernel/reset.c
+++ b/arch/riscv/kernel/reset.c
@@ -20,6 +20,7 @@ void machine_restart(char *cmd)
 	do_kernel_restart(cmd);
 	while (1);
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_halt(void)
 {
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 5aab59ad56881..fd2394af0d43a 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -276,6 +276,7 @@ void machine_restart(char *command)
 		console_unblank();
 	_machine_restart(command);
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_halt(void)
 {
diff --git a/arch/sh/kernel/reboot.c b/arch/sh/kernel/reboot.c
index 5c33f036418be..36b6c61f3b129 100644
--- a/arch/sh/kernel/reboot.c
+++ b/arch/sh/kernel/reboot.c
@@ -83,6 +83,7 @@ void machine_restart(char *cmd)
 {
 	machine_ops.restart(cmd);
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_halt(void)
 {
diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c
index 3b9794978e5bc..30a1674683946 100644
--- a/arch/sparc/kernel/process_32.c
+++ b/arch/sparc/kernel/process_32.c
@@ -104,6 +104,7 @@ void machine_restart(char * cmd)
 	prom_feval ("reset");
 	panic("Reboot failed!");
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_power_off(void)
 {
diff --git a/arch/sparc/kernel/reboot.c b/arch/sparc/kernel/reboot.c
index 69c1b6c047d53..53adef425d7de 100644
--- a/arch/sparc/kernel/reboot.c
+++ b/arch/sparc/kernel/reboot.c
@@ -52,4 +52,5 @@ void machine_restart(char *cmd)
 	prom_reboot("");
 	panic("Reboot failed!");
 }
+EXPORT_SYMBOL(machine_restart);
 
diff --git a/arch/um/kernel/reboot.c b/arch/um/kernel/reboot.c
index 48c0610d506e0..4b764311efb89 100644
--- a/arch/um/kernel/reboot.c
+++ b/arch/um/kernel/reboot.c
@@ -47,6 +47,7 @@ void machine_restart(char * __unused)
 	uml_cleanup();
 	reboot_skas();
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_power_off(void)
 {
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index b29657b76e3fa..b48c30ead7167 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -733,6 +733,7 @@ static void native_machine_restart(char *__unused)
 		machine_shutdown();
 	__machine_emergency_restart(0);
 }
+EXPORT_SYMBOL(machine_restart);
 
 static void native_machine_halt(void)
 {
diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index ed184106e4cf9..a84cc934300d5 100644
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c
@@ -564,6 +564,7 @@ void machine_restart(char * cmd)
 {
 	platform_restart();
 }
+EXPORT_SYMBOL(machine_restart);
 
 void machine_halt(void)
 {
-- 
2.32.0.554.ge1b32706d8-goog

[PATCH 2/3] reboot: Export reboot_mode

[Lee Jones]

From: Elliot Berman <eberman@codeaurora.org>

Export reboot_mode to support kernel modules wishing to modify reboot_mode.

Signed-off-by: Elliot Berman <eberman@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 kernel/reboot.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/reboot.c b/kernel/reboot.c
index a6ad5eb2fa733..7ca414aa070b6 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -32,7 +32,9 @@ EXPORT_SYMBOL(cad_pid);
 #define DEFAULT_REBOOT_MODE
 #endif
 enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
+EXPORT_SYMBOL_GPL(reboot_mode);
 enum reboot_mode panic_reboot_mode = REBOOT_UNDEFINED;
+EXPORT_SYMBOL_GPL(panic_reboot_mode);
 
 /*
  * This variable is used privately to keep track of whether or not
-- 
2.32.0.554.ge1b32706d8-goog

[PATCH 3/3] power: reset: Enable tristate on restart power-off driver

[Lee Jones]

From: Elliot Berman <eberman@codeaurora.org>

Since reboot_mode is an exported symbol, restart power-off driver can be
compiled as module.

Signed-off-by: Elliot Berman <eberman@codeaurora.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/power/reset/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 4d1192062508d..e155b2e2a75c4 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -192,7 +192,7 @@ config POWER_RESET_REGULATOR
 	  power regulator defined in the devicetree.
 
 config POWER_RESET_RESTART
-	bool "Restart power-off driver"
+	tristate "Restart power-off driver"
 	help
 	  Some boards don't actually have the ability to power off.
 	  Instead they restart, and u-boot holds the SoC until the
-- 
2.32.0.554.ge1b32706d8-goog

Re: [PATCH 3/3] power: reset: Enable tristate on restart power-off driver

[Sebastian Reichel]

[-- Attachment #1: Type: text/plain, Size: 1086 bytes --]

Hi,

On Tue, Aug 03, 2021 at 04:54:52PM +0100, Lee Jones wrote:
> From: Elliot Berman <eberman@codeaurora.org>
> 
> Since reboot_mode is an exported symbol, restart power-off driver can be
> compiled as module.
> 
> Signed-off-by: Elliot Berman <eberman@codeaurora.org>
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---

Acked-by: Sebastian Reichel <sre@kernel.org>

-- Sebastian

>  drivers/power/reset/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index 4d1192062508d..e155b2e2a75c4 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -192,7 +192,7 @@ config POWER_RESET_REGULATOR
>  	  power regulator defined in the devicetree.
>  
>  config POWER_RESET_RESTART
> -	bool "Restart power-off driver"
> +	tristate "Restart power-off driver"
>  	help
>  	  Some boards don't actually have the ability to power off.
>  	  Instead they restart, and u-boot holds the SoC until the
> -- 
> 2.32.0.554.ge1b32706d8-goog
> 

[-- Attachment #2: signature.asc --]
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Re: [PATCH 1/3] arch: Export machine_restart() instances so they can be called from modules

[Geert Uytterhoeven]

On Tue, Aug 3, 2021 at 5:56 PM Lee Jones <lee.jones@linaro.org> wrote:
> A recent attempt to convert the Power Reset Restart driver to tristate
> failed because of the following compile error (reported once merged by
> Stephen Rothwell via Linux Next):
>
>   ERROR: "machine_restart" [drivers/power/reset/restart-poweroff.ko] undefined!
>
> This error occurs since some of the machine_restart() instances are
> not currently exported for use in modules.  This patch aims to rectify
> that.
>
> Signed-off-by: Lee Jones <lee.jones@linaro.org>

> NB: If it's safe to omit some of these, let me know and I'll revise the patch.

How do you plan to handle that? Isn't this an all-or-nothing export?

>  arch/m68k/kernel/process.c         | 1 +

Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 1/3] arch: Export machine_restart() instances so they can be called from modules

[Lee Jones]

On Mon, 09 Aug 2021, Geert Uytterhoeven wrote:

> On Tue, Aug 3, 2021 at 5:56 PM Lee Jones <lee.jones@linaro.org> wrote:
> > A recent attempt to convert the Power Reset Restart driver to tristate
> > failed because of the following compile error (reported once merged by
> > Stephen Rothwell via Linux Next):
> >
> >   ERROR: "machine_restart" [drivers/power/reset/restart-poweroff.ko] undefined!
> >
> > This error occurs since some of the machine_restart() instances are
> > not currently exported for use in modules.  This patch aims to rectify
> > that.
> >
> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> 
> > NB: If it's safe to omit some of these, let me know and I'll revise the patch.
> 
> How do you plan to handle that? Isn't this an all-or-nothing export?

That's the way I see it, but I don't have an in-depth knowledge of all
of the architectures.  There may be a method there that isn't part of
the core API.  If that's the case, I can drop the export.

> >  arch/m68k/kernel/process.c         | 1 +
> 
> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

Thanks Geert.

I'll pick this up when I do the re-spin shortly.

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

[PATCH 3/3] power: reset: Enable tristate on restart power-off driver

[Lee Jones]

From: Elliot Berman <eberman@codeaurora.org>

Since reboot_mode is an exported symbol, restart power-off driver can be
compiled as module.

Signed-off-by: Elliot Berman <eberman@codeaurora.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Sebastian Reichel <sre@kernel.org>
---
 drivers/power/reset/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 4d1192062508d..e155b2e2a75c4 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -192,7 +192,7 @@ config POWER_RESET_REGULATOR
 	  power regulator defined in the devicetree.
 
 config POWER_RESET_RESTART
-	bool "Restart power-off driver"
+	tristate "Restart power-off driver"
 	help
 	  Some boards don't actually have the ability to power off.
 	  Instead they restart, and u-boot holds the SoC until the
-- 
2.32.0.605.g8dce9f2422-goog